>>5072882To be fair, if you use hiragana for an entire sentence without katakana to differentiate, it will become very confusing very fast.
For example, ソファにすわった vs そふぁにすわった, the katakana allows you to quickly identify what's needed to be interpreted as an English word and isolate it
or you might accidentally say "so funny" instead in this caseSimilarly, without Kanji, sentences would pretty much become twice as long and much more difficult to understand.
For example, looking at the symbols 図書館 allows you to quickly grasp exactly what's being written, while looking at としょかん requires you to read the entire thing, then separate it from the rest of the sentence before putting it together to mean library, rather than having specific symbols for it.
There's probably a better solution to simplify the language but there are always flaws in it.
Just like any other language, especially the patchwork that is English. 
